import java.util.Scanner;
import java.sql.*;
public class Demo1 {
    /**
     *  1.注册驱动
     *  2.获取连接
     *  3.创建表结构对象
     *  4.执行sql语句
     *  5.操作结果
     *  6.关闭连接
     */



    public static void main(String[] args) throws SQLException{
        Statement stmt = null;
        ResultSet rs = null;
        Connection conn = null;
        try {
            //1.注册数据库的驱动
            Class.forName("com.mysql.cj.jdbc.Driver");
            //2.通过DriverManager获取连接
            String url = "jdbc:mysql://localhost:3306/jdbc?serverTimezone=GMT%2B8&useSSL=false";
            String username = "root";
            String password = "yu2003..";
            conn = DriverManager.getConnection(url, username, password);
            /**
             * 静态sql语句用Statement
             * 动态sql语句用prepareStatement
             */
            Scanner sc = new Scanner(System.in);
            System.out.println("请输入你的旧账号名:");
            String n1 = sc.next();
            System.out.println("请输入你的旧密码:");
            String p1 = sc.next();
            System.out.println("请输入你的新账号名:");
            String n2 = sc.next();
            System.out.println("请输入你的新密码:");
            String p2 = sc.next();
            String updateSQL = "update user set name=? ,password=? where name =? and password=?";
            PreparedStatement ps = conn.prepareStatement(updateSQL);
            ps.setString(1,n2);
            ps.setString(2,p2);
            ps.setString(3,n1);
            ps.setString(4,p1);
            int res = ps.executeUpdate();
            System.out.println(res);
            if (res>0){
                System.out.println("账号密码更新成功");
            }else{
                System.out.println("账号密码更新失败");
            }
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } finally {
            //回收数据库资源
            if (rs != null) {
                try {
                    rs.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
                rs = null;
            }
            if (stmt != null) {
                try {
                    stmt.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
                stmt = null;
            }
            if (conn != null) {
                try {
                    conn.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
                conn = null;
            }
        }
    }
    }

